1. Field of the Invention
The invention relates to a radio frequency (RF) detecting device, more particularly to an isolation detecting device capable of measuring a degree of isolation between two RF circuits.
2. Description of the Related Art
Because of the increased demand for wireless products, current portable wireless devices, such as smart phones or other mobile devices, often come installed with multiple wireless communication standards, such as WiFi, EDGE, HSPA, EVDO, LTE, and/or Bluetooth. In order to accommodate simultaneous use of these different standards, it is essential to have sufficient degrees of isolation among these different standards. Therefore, to quickly measure the degrees of isolation among these standards has become increasingly important.
FIG. 1 depicts a conventional way of measuring the degree of isolation between two wireless standards, such as between an LTE communication system 100 and a WiFi communication system 200. This is done by disconnecting (through unwelding) an antenna 103, 203 from a connector 101, 201 between the antenna 103, 203 and a back-end RF circuit 104, 204 of each of the LTE communication system 100 and the WiFi communication system 200, and then connecting (through welding) the antenna 103, 203 to a network analyzer 300 using an RF coaxial cable 102, 202. The network analyzer 300 performs two-port small-signal S-parameter analysis to measure the S21 parameter that represents the degree of isolation between the antenna 103 of the LTE communication system 100 and the antenna 203 of the WiFi communication system 200. However, this approach requires the removal of the connections between the antennae 103, 203 and the respective connectors 101, 201 and is thus unduly invasive, and the antennae 103, 203 need to be reconnected with the respective connectors 101, 201 after the measurement is done and is therefore labor intensive. In addition, once the position of one of the antennae 103, 203 is adjusted, this troublesome process has to be carried out all over again. Further, the network analyzer 300 has the downside of only being capable of measuring the degree of isolation with respect to small signals.